Gov. Jerry Brown, touting what he called a “high bar” on climate change, on Wednesday issued an ambitious new greenhouse gas reduction target for the state.

The target, contained in an executive order and expected to be folded into pending legislation, seeks to reduce emissions in California 40 percent below 1990 levels by 2030.

The goal is in line with one adopted by the European Union last year, and proponents characterized it as the most aggressive in North America.

“With this order, California sets a very high bar for itself and other states and nations, but it’s one that must be reached – for this generation and generations to come,” Brown said in a prepared statement.

Republicans and business representatives, however, cautioned that the regulations required to meet such a goal could raise the cost of doing business and hurt low- and middle-income energy consumers.

Brown has said California will meet or exceed its previous goal of reducing emissions to 1990 levels by 2020, and he offered Wednesday’s goal as an interim step to reducing emissions to 80 percent of 1990 levels by 2050.

In his executive order, Brown wrote that the 2030 target is “necessary to guide regulatory policy and investments in California in the midterm, and put California on the most cost-effective path for long-term emission reductions.”

Brown’s order requires the state to consider climate change impacts in California’s five-year infrastructure plan and to assess how climate change will affect California infrastructure and industry. It also requires state agencies to factor climate change into planning and investment decisions.

In such decisions, Brown said in his order, “priority should be given to actions that both build climate preparedness and reduce greenhouse gas emissions.”

The issuance of a more ambitious carbon reduction goal has been expected since September, when Brown said the state would meet its existing goal and that he would announce a new one within six months.

A longtime champion of environmental causes, Brown has argued that California’s policies – and climate-change agreements forged between this state and other sub-national governments – could help pressure heads of state as they prepare to negotiate a climate change treaty in Paris later this year.

“I believe that from the bottom up we can make real impact, and we need to join together,” Brown said last year.

Christiana Figueres, the Costa Rican diplomat and executive secretary of the United Nations Framework Convention on Climate Change, said in a prepared statement that Brown and California “have clearly understood, internalized and articulated the science of climate change” and have “aligned the state to the growing global understanding” of its challenges.

Environmentalists lauded the target. But their praise of Brown – as on other matters in recent years – was tempered by criticism of his permissiveness of hydraulic fracturing, a controversial form of oil extraction.

Kassie Siegel of the Center for Biological Diversity’s Climate Law Institute said in a prepared statement that Brown “deserves credit for this important step towards fighting global warming, but the governor continues to undermine his own plans by backing fracking.”

Brown proposed dramatically expanding California’s greenhouse gas reduction laws in his State of the State address in January, and Senate President Pro Tem Kevin de León announced legislation the following month to enact much of the governor’s proposal.

The legislation would cut petroleum use in half by 2030 and expand, from one-third to one-half, the proportion of electricity that California derives from renewable sources such as wind and solar.

De León said Wednesday that Brown’s target shows that California “leads the entire country” on greenhouse gas reduction efforts.

Many conservatives believe the effects of global warming are overstated, and they object to the cost of environmental regulations.

Bob Huff, the Republican state Senate leader, said in a prepared statement that California’s carbon reduction goals are already the nation’s most stringent and that “before moving the goal post, we should be careful about the impact of increased energy costs.”

“At what point does being on the leading edge of climate change and environmental reform impact our ability to create or sustain jobs?” Huff said.

Rob Lapsley, president of the California Business Roundtable, said the 40 percent goal may be achievable, but he worries regulations designed to achieve it could dramatically increase business costs.

“The key question is how prescriptive are they going to be from a regulatory standpoint?” he said. “That will determine how expensive it becomes.”

Brown’s office announced the target as the Democratic governor traveled to the Los Angeles area to speak on climate change, first at a conference on climate policy and carbon markets in Los Angeles, then at a Milken Institute conference in Beverly Hills.

At the Milken Institute, Brown criticized Republicans in Washington who are skeptical of climate change.

“What I think we really can appreciate here is through three governors – Gov. (Gray) Davis, Gov. (Arnold) Schwarzenegger and now myself,” he said, “there’s been a California effort that is unique, in that we have taken steps ourselves to deal with reducing emissions.”